Seoul's luxury hotels are competing for diners with premium takes on boyangsik, the restorative dishes Koreans have long eaten to power through the hottest weeks of the year. The tradition peaks during boknal, the three hottest days of the lunar calendar, when samgyetang, eel and croaker dishes are believed to replenish energy drained by the heat. Chobok, the first of the three days, falls on July 15 this year. The second, jungbok, falls on July 25 and the third, malbok, on Aug. 14. At Park Hyat